The full moon on Friday 31, 2015 is not a typical full moon.
This is a blue full moon, a phenomenon which only occurs approximately every three years. But although its name suggests otherwise, the moon will not turn blue!
The blue moon is indeed the name given to the second full moon in a month of the common calendar.
The first full moon of July 2015 took place on the 2nd, and the next will rise on the 31st.
This phenomenon is actually pretty rare as the next blue moon will only reappear in 2018 – in January and March. Yes can you imagine that? There will be two blue moons and this phenomenon only occurs three to seven times each century. The previous year with two blue moons was 1999.
Origin of the name
It is believed that the name Blue Moon dates from medieval Europe and has its origins in the Old English word “belewe” which means “traitor”. The double full moon was not well received at the time because it usually meant lengthening the period of fasting during Lent.
Of course, there are those who say that on this special day, the full moon is blue or has a bluish tint. Nothing further away from reality. Sometimes the moon may have a slight bluish cast, but that only happens when particles suspended in the atmosphere filter the light of the moon. These particles usually arise from large forest fires or volcanic eruptions.